Epcot

Anna and Elsa Meet and Greet - there is a painting of trolls from the old Maelstrom, Norway ride. Three trolls at top and below that is the troll with one eye closed. It's in the hallway before the room where they separate groups.

Some of the lights for the IllumiNations show in Epcot are disguised as part of the large rocks in front of Canada in the World Showcase. They pop up for the show and then recede to be unnoticed as the tops of the rocks.

The Coke iceboxes at the Refreshment Outpost at Epcot have surprises when their lids are raised. One makes the sound of a bottle cap being opened and the bubbling sound of soda carbonation. Other boxes spray water when opened.

Sometimes, but not always, during a meal at Chefs de France, a cast member may offer you some cheese only when the serving dome is lifted an animatronic Remy may be Hiding next to the cheese. This is (or was) a fun Surprise that seems to be becoming more unusual.